It is often required when planting seeds to have the seeds placed in the soil at regular distances apart and at constant depth from the soil surface. The seeds need to be adequately protected from pests, for the earth to be disturbed marginally around the seed and the rest of the earth to be disturbed as little as possible. It is also required when planting that the whole planting device can be turned easily whilst in operation to allow for turning in the field and planting in non rectilinear lines. For economic and environmental reasons it is desirable that as little fuel as possible is burned during the crop establishment practices.
Current common soil opener devices require a finely tilled seed bed or in cases where conservation or zero tillage is used as a farming method then the planters are very heavy and or large in order to carry out accurate soil opening and seed placement duties. In nearly all cases these machines open soil slots that do not protect the seeds particularly well and are not very accurate, thus attacking of the seed by pests and the variances in seed depth and placement result in lower crop germination rates and uneven crop growth which affect the ultimate crop yield. In cases of planting seed into a finely tilled seed bed a minimum of two prior soil activities need to take place before a fine seed bed is achieved. Both of these prior activities require large amounts of power and draught which means large, heavy, powerful tractors are used and these compact the soil and burn large amounts of fuel. Other possible severe results of using a finely tilled seed bed are depletion of the soil's fertility, self protection mechanisms and moisture content. In cases where conservation or zero-tillage is used the seeds are planted directly into the field without any prior soil activities and thus the problems of large amounts of fuel being burnt, soil compaction, fertility, protection and moisture loss are significantly reduced or eliminated. However in order for the current planting devices to open a satisfactory soil slot, using conservation and zero-tillage practices, a heavy and or large planting machine is required which is hard to turn in the field and such a machine still has a high draught requirement which requires a large heavy tractor. Some current soil openers can suffer from blockages caused by soil and other debris.
Some soil openers which are known in the art are discussed below.
WO 82/03962 discloses a pit-forming implement capable of forming a series of separate pits which are capable of collecting surface water. The implement comprises a plurality of soil openers which are distributed directly from a drum, via apertures.
SU 459185 discloses a tree seedling planter for planting seedlings, in the form of hole dibber with a spring-loaded rocking arm, one end of which is provided with a dibbing point.
EP 0738460 discloses an apparatus for planting young plants, wherein the plants are deposited by a human operator. The apparatus comprises a plurality of soil openers, wherein each of the soil openers is pivoted to a support on a main frame such that it oscillates with the advancing movement of the frame and makes vertical holes in the soil to receive the plants.
U.S. Pat. No. 1,604,624 discloses a planting apparatus in which a plurality of spouts are mounted on a rotating drum.
U.S. Pat. No. 4,637,328 discloses a mechanically-operated no-till planting apparatus for repeatedly and successively penetrating the soil to a predetermined depth at a predetermined spacing, and depositing a quantity of seed or fertiliser.